You install Update Rollup 4 for Microsoft Exchange Server 2010 SP2 on an Exchange Server 2010 SP2 server that is running against a BlackBerry Enterprise Server.
The BlackBerry Enterprise Server uses MAPI or Collaborative Data Objects (CDO) instead of Exchange Web Services (EWS) to communicate with Exchange servers.
A mailbox on a BlackBerry mobile device contains many folders. For example, the mailbox contains more than 5000 folders.
In this scenario, you encounter one or more of the following issues:
Delivery of email messages to a mailbox on a BlackBerry mobile device is delayed.
It takes longer than expected to scan a folder hierarchy in the mailbox. For example, before you install Update Rollup 4 for Exchange Server 2010 SP2, a scan of a folder hierarchy takes about 5 minutes. After you install Update Rollup 4 for Exchange Server 2010 SP2, a scan of a folder hierarchy takes about 30 minutes to 1 hour.
The Microsoft Exchange Information Store process (Store.exe) on the Exchange Mailbox server consumes too many CPU resources.
Some BlackBerry Enterprise Server event log entries are logged on the Exchange Mailbox server. Before you install Update Rollup 4 for Exchange Server 2010 SP2, few entries are logged, or no entries are logged.
Some events are logged in the BlackBerry Messaging Agent (MAGT) log. These events resemble "Busy Working" threads that are described in the following article in the BlackBerry Knowledge Base:
This issue occurs because the Exchange server creates a new administrator session every time the server tries to bind a delegate to each folder and retrieve folder properties for the delegate. Additionally, because the server sets a certain flag for each folder bind, a high-cost process flow occurs. Therefore, when BlackBerry Enterprise Server requests the properties of many folders, the issue that is described in the "Symptoms" section occurs.
To resolve this issue, install the following update rollup:
2803727 Description of Update Rollup 1 for Exchange Server 2010 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the issue, click the following article numbers to view the articles in the Microsoft Knowledge Base:
2726897 Admin sessions are exhausted as a result of delegate access in an Exchange Server 2010 environment
2706690 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 2
2797529 Email message delivery is delayed on a Blackberry mobile device after you install Update Rollup 4 for Exchange Server 2010 SP2
2810616 Email message delivery is delayed on a Blackberry mobile device after you install Update Rollup 4 for Exchange Server 2010 SP2
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.